Attachment for comparators



19361 R. o. BE'ARDS'LEY 2,931,21

ATTACHMENT FOR COMPARATORS Filed May 9, 1955 2 Sheet'S -Sheet l l /4 I U W Feb. 18, 1936. R. o. BEARDSLEY ATTACHMENT FOR COMPARATORS Filed May 9 1955 2 Shets-Sheet 2 Patented Feb; 18,1936

UNITED STATES ATTACHMENT For; comamrons Robert 0. Beardsley, Jones 8; Lamson Springfield, Vt., assignor to Macbin field, Vt., a corporation of 1: Company, Spring- Vermont Application May a, 1935, sumac. 20,564

4 Claims. (01. as -24) This invention relates to' an illuminating attachment for comparators of the kind shown and described in the Hartness and Porter patent No. 1,703,933, issued March'5, 1929, or for the pedestal type of comparator shown and described in the Beardsley, Bysshe and Finn application See- I rial No. 747,200, filed October 6, 1934, for Comparators. In comparators of this type, a beam of light is usually projected across a portion of the periphery of the object to be tested, the magnified shadow image of this contour portion be ing thrown upon a screen where it can be compared with a standard diagram. Thusobjects such as scre'wthreads, gear teeth and the like, may be easily and accurately'tested. In the'case of other objects,-'.such as type faces, punches, dies, etc.,' where'it is desired to obtain an image of a surface portion, strong illumination of such surface is required as "the image is formed by light reflected from the surface. According to the present invention, convenient means is provided for furnishing such illumination when de sired. The illuminating means is adjustable so as to concentrate beams of light on the work when the latter is held in proper position in line with the optical axis of the lens system through which the image of the work is projected in. inagnifled form on the screen, the light beams being arranged to fall on the surface of the work which is opposite the lens system. It is an object of the invention to provide illuminating means which can be readily-moved out of the way into inoperative position whenynot wanted and may be readily moved back into operative position without disturbing any of the adjustments thereof. This illuminating means. is thus available for use in supplementing'the usual illuminating means by which a light beam is pro- Jected directly into' the lens system across a portion of the contour of thework.

For a more complete understanding of the invention, reference may be had to the description of an embodiment thereof which follows, and to the drawings of which Figure 1 is a side elevation of a pedestal type of comparator having an embodiment of the present invention attached there Figure 2 is a perspective view of one of the pivoted arms on which the illuminating units are o ted- Figure 3 is a perspective view of a stationary bracket on which-the arm shown in Figure 2 is ,plvotally suppo Figure 4 is a perspective view of one of t e Ji li- 55-minatihg units.

Figure 5 is a fragmentary plan view ofthe comparator showing the illuminating units and their supports in operative position.

Figure 6 is a similar plan view showing the illu-f minating units in their inoperative position.

The comparator illustrated in Figure 1 includes a housing III which may be mounted on a suitable standard or pedestal, II. On the front side of-the pedestal I! are brackets It and it which actas guides for a vertical ram l8 on the upper end of which is an adjustable work table 20. This table may be'raised or lowered 'bysuitable means such as a hand wheel 22 which bears on the upper face of the bracket l4 and is screwthreaded on a portion 24 of-the ram l8. The

work table is capable of various adjustments as described in application Serial No. 747,200, hereinbefore referred to. Projecting through the housing III is a magnifying lens system, the external portion of which is shown at 30. Work to be tested is mounted on the table 20 and is adjusted so that the portion of the work which is to betested is alined with the optical axis of the lens system 30. An image of this portion ofthe work is reflected by a mirror within the housing l0 onto a translucent screen as described in the afore-inentioned patent and application.

According to the present invention, a pair of illuminating units is mounted in such a way as to be capable of projecting beams of light against thegportion of the work facing the lens system 30 so that a portion of the light is reflected into the lens system to form, the image. As illumination of thissort is desired onlyfor the testing of certain 'kinds of objects, the illuminating units are mounted so that they can be readily moved into and out of operative position without disturbing the adjustments thereof. As shown in Figure 4, each illuminating unit comprises a lamp house 32 enclosing a lamp (not shown), and a prism holder 34 on which is carried a reflecting prism CI. The lamp house is provided with a condensing lens mounted in a lens holder ll which is directed toward the prism 36. The beam of lightpas'slng through the lens holder 38 to the prism 3C is internally reflected by the prism and emerges from the emergence face ll of the prism,

which, as shown. is preferably convex or is adiacent to a convex lens so as to concentrate the beam of light on the portion of the work which is in line with the optical axis of the lens system 3|. 7 The lamp, lamp house and prism holder .are preferably constructed so as to be capable of various adjustments for the purpose of directvl lthe li ht beam asdesired. '1he lamp house screw 60 passes for threaded engagement with the outer end of the arm 46. Thus the illuminatin unit may be longitudinally or rotatably adjusted with reference to the arm 46 and may be clamped in any desired position of adjustment by setting up on the thumbscrew 60. The arm 46 is provided with a pivot pin 62 adapted to rotate in a socket 53, the latter being supported by a stationary bracket which may be secured to the housing It or to any other convenient stationary member associated therewith. As indicated in Figure 2, the arm 46 may be provided with a suitable ing adapted to engage the bracket 55 to limit the swing of the arm 46 when the illuminating unit is swung to its inoperative position as shown in Figure 6. The-lug 66 is preferably formed in such a manner as to prevent contact between any portion of the illuminating unit and the housing It, no matter what position of adjustment the illuminating unit may be with reference to the arm 46. In'order to determine the position: of the arm 46 when the illuminating unit is in its operating position, an abutment screw 66 may be threaded through the arm 46 to engage a stationary lug 66 on the bracket 66. The screw 66 may be clamped in any position of adjustment as by a setscrew 16. The screw 66 thus makes it easy to move the arm 46 into correct operative position. The arm may be held in this position or in any other position by a binding screw 12, which, when set up, clamps the pivot pin 62 in the socket 63.

It 'is evident that various modifications and changes may be made in the structure herein shown and described without departing from the spirit or scope of the invention defined in the following claims.

I claim:-

1. In a comparator'of the character described having .a housing, a horizontal optical instrument projecting through said housing, and a worksupporting table in front of said housing; a hinged bracket mounted on said housing, an arm pivotally mounted on said bracket, a support member adjustably fixed at the free end of said arm. a lamp house and a prism mounted in spaced relation on said support member, and means for adjustably limiting the angle of swing of said arm.

2. In a comparator of the character described including a horizontal optical instrument and means for supporting work in line with the optical axis of said instrument; an illuminating unit swingable into and out of a predetermined adjustable position of operation, said unit comprising a lamp, a lamp house therefor, a prism, and a prism holder in spaced relation to said lamp house, and means for supporting said illuminating unit, said supporting means including an arm swingable in a horizontal plane, a cross piece ad- Justably mounted on said arm, a lamp house and prism holder being mounted on said cross piece.

3. In a comparator of the character described including an optical instrument, means for supporting said instrument, and an adjustable table for holding the work in of said instrument; a pair of hinged brackets pivotally mounted in said supporting means, a cross piece adjustably mounted on the free end of said bracket, a lamp house and a prism holder mounted on each said cross piece, a lamp in each lamp house, a prism in each prism holder, and means on each said bracket for limiting the pivotal motion thereof to one extreme position in which the lamp and prism are in operative position relative to the work, and to an inoperative position wherein the lamp house and prism holder are held in said supporting means.

4. In a comparator of the character described including a housing, an optical instrument projecting through said housing, and a table adjustable to support the work in line with the optical axis of said instrument; a pair of hinged brackets pivotally mounted on said housing, an illuminating unit adiustably mounted on each said bracket to swing into and out of operative position without change of adjustment, each said unit comprising a cross piece adiustably supported on its bracket, a lamp house and a prism holder mounted on the cross piece in spaced relation to each other, a lamp in said lamp house, and prism in said holder, stop means for limiting the extreme positions of each said bracket. one of said extreme positions being the operative position, and means for clamping each said bracket in either extreme position.

line with the optical axis' 

